Title

Author

Date of Award

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Kevin France

Second Advisor

John Bally

Third Advisor

Jeremy Darling

Fourth Advisor

Jason Glenn

Fifth Advisor

Mihály Horányi

Abstract

To further our understanding of how forming stars and planetary atmospheres can survive large inputs of radiative and kinetic energy, I have undertaken observational studies of the Orion BN/KL outflow and a sample of nearby M dwarfs with exoplanets. The Orion BN/KL explosive outflow is a spectacular, wide-angle ensemble of hundreds of protostellar-like jets. With near-IR integrated intensity maps of 13 ro-vibrational H2 lines, I determined the excitation conditions across the arcminute-scale, wide-angle BN/KL outflow at 1" resolution. The warm H2 populations (~2000-2500 K) are consistent with collisional excitation by shocks, but small areas are likely excited radiatively. As a potentially common phenomenon in massive star forming regions and a test bed for shock models due to its brightness, the BN/KL is important to characterize in detail.

Exoplanets orbiting stars less massive than the Sun are prime targets for current and near-future atmospheric characterization efforts, because they are nearby and offer larger signals. However, it is an open question whether a habitable-zone rocky planet could maintain an atmosphere through all of the expected mass-loss processes driven by the parent star, especially from high-energy photons and particles. I have characterized the far-UV spectra of 11 K and M dwarfs, determined a correlation between the far- and near-UV spectra and more easily-obtained optical spectra, and developed a method for estimating stellar particle output associated with flares. These are useful tools for evaluating the likelihood that a M dwarf terrestrial planet has a substantial atmosphere.